Paper Title
In Silico Characaterization of Xylose Reductase using Computational Tools

Abstract
Xylose reductase (EC 1.1.1.21), an industrially important enzyme is produced mainly by bacteria, yeast, mold and algae. The major application of xylose reductase is in the production of xylitol from xylose with the help of NADH and/or NADPH as coenzyme. Xylitol has wide range of applications in industrial sector like food, medical, pharmaceutical, odontological and cosmetics due to its unique properties. The present in silico study deals with the use of bioinformatics tools for the characterization of xylose reductase. Xylose reductase protein sequences from various microorganisms (Candida boidinii Q8X19; Candida tropicalis P87039; Candida parapsilosis Q6Y0Z; Aspergillus niger A2Q8B5; Aspergillus flavus B8N195; Enterobacter aerogenes A0A0H3FX88) were retrieved using Uniprot. The physicochemical properties of xylose reductase from selected microorganisms were computed using Expasy’s ProtParam tool. The pI of all the organisms were predicted to be acidic in nature and this enzyme was found to be stable among all the microorganisms except Enterobacter aerogenes A0A0H3FX88. The negative value of GRAVY among all the organisms showed its better interaction with water. Protscale’s Kyte and Doolittle hydropathy plots were also computed and the transmembrane region of this enzyme was found to contain more number of hydrophilic amino acids. The secondary structure was predicted using Expasy’s GOR IV and SOPMA tools which showed the dominance of random coil conformation in the protein. Multiple sequence analysis was done by Clustal Omega and phylogenic tree was constructed by Mega 6.0 software using Neighbor Joining Method. The 3D structure of xylose reductases were obtained by RaptorX Structure Prediction server. Keyword - Xylose reductase, ProtParam, Protscale, Mega 6.0, RaptorX